

Birth of the Virgin, Christ’s nativity and Grotesques (1490-1494), monochrome frescoes (or grisaille), with golden heightening and azurite inserts, made by Francesco di Giorgio Martini, and his collaborators, inside the Bichi Chapel. 
These frescoes were traced in 1977 under the faded paintings related to the chapel’s restoration work planned by the architect Vanvitellli (1755) after the fire of 1747. The frescoes were restored in 1982.
Sepulchral monument of the Frondi family (1560 – 1571), a fresco by Bartolomeo Neroni, alias ‘il Riccio’, discovered under the plaster of St. John the Baptist’s chapel in the Seventies of the twentieth century.
The pictorial surface was subject to a reconsolidation in 1979, after various layers of plastering had been removed.